1. Field of the Invention
The present invention relates to a method of treating or preventing colitis by modulating the colitis-inducing effects of the cytokine interleukin-13 (IL-13). The invention also relates to a method of treating or preventing colitis by modulating the colitis-inducing effects of NK-T cells Further provided is a method for screening substances for their effectiveness in reducing the inflammatory response of colitis and preventing colitis in a mouse model.
2. Background Art
Human inflammatory bowel diseases (IBDs), Crohn's disease (CD), and ulcerative colitis (UC), are believed to be due to an abnormal mucosal T cell responsiveness to bacterial antigens in the gut lumen (Sartor, 1995). In CD, the responding T cells exhibit a Th1 phenotype and thus produce large amounts of interferon-γ (IFN-γ) and tumor necrosis factor (TNF-α). IL-12 secretion, the driving force of Th1 differentiation is also increased (Parronchi et al., 1997). In UC, the responding T cell is less well defined. In this case, whereas Th1 cytokine production is normal or decreased and some Th2 cytokine production (IL-5 and IL-10) is increased, the production of the “signature” cytokine of the Th2 response, IL-4, is not increased (Fuss et al., 1996).